In this second installment of the human stories behind herpetological research, we hear the story behind a recent publication in SSAR’s Journal of Herpetology. That article by Nelson, Niemiller, and Fitzpatrick is entitled “Co-occurrence and Hybridization between Necturus maculosus and a Heretofore Unknown Necturus in the Southern Appalachians”, and you can download the Open Access PDF here. Below is an account of the research from first author, Stephen Nelson.
In 2009, I started volunteering for hellbender surveys in southeastern Tennessee. During these surveys, we encountered mudpuppies every once in a while. During some of the oohs and aahs of other surveyors, Michael Ogle and Dr. Matthew Niemiller made comments about how small the mudpuppies were and that they looked “weird”. I had only encountered mudpuppies during these hellbender surveys, and so to me, they looked like every other mudpuppy we had encountered, and I didn’t think twice about it.
During the summer field season of 2011, I worked as a field tech for hellbender research under Dr. Rod Williams. During these hellbender surveys we encountered a Common Mudpuppy that could have been a stunt double for the Loch Ness Monster. It was quite large and very different looking from the ones I was used to seeing, and it matched the descriptions I had read in books and articles. Right then, it hit me that maybe Matt and Michael were onto something!
When I returned home, I spoke with Dr. Ben Fitzpatrick during a meeting about another undergraduate project I was working on and mentioned that there were some “weird” looking waterdogs in southeastern Tennessee and asked what he thought about taking some tissue samples and measurements to see if there might be anything “weird” about them, after all. The next summer field season, we captured 9 mudpuppies. After scanning field guides and books for keys and
descriptions of species, I thought that there might be some potential for this smaller “weird” waterdog species to be the Black Warrior River Waterdog (Necturus alabamensis). After generating our own sequence data, we combed through Genbank for other Necturus sequences and compiled a gene tree. Interestingly enough, we had sequence data that suggested there were two different species of waterdogs from southeastern Tennessee—the first being the described species, the Common Mudpuppy, and the second being something other else entirely!
The following two field seasons, we collected more samples from southeastern Tennessee and thanks to the generosity of other researchers, we were able to acquire reference tissues from most other species. With this expanded sampling effort and reference tissue we were able to determine that there are indeed two distinct species of waterdogs in southeastern Tennessee, the Common Mudpuppy and one that shares its most recent common ancestor with the Neuse River Waterdog (Necturus lewisi). For more information, check out our recently published article in the Journal of Herpetology!
We are now working on determining if the “weird” waterdog in East Tennessee is a distinct species from the Neuse River Waterdog, using eDNA to determine distribution of both species within the region, and collecting life history data on both species. This project was started and predominately carried out while I was an undergraduate, and I am greatly indebted to the different researchers and mentors who have helped me with this project and other endeavors. It is fascinating to uncover an additional species within Tennessee, and perhaps equally fascinating is the discovery of how little we know about “common” species, like the Common Mudpuppy, and how even an undergrad can help fill knowledge gaps. I am very fortunate that this undergraduate project has become larger and I am able to continue studying these “water devils”.